The present invention relates to a roll for a paper/board machine or for a paper/board finishing device and a method for fastening an inner tube in the interior of a roll of a paper/board machine or a paper/board finishing device.
Polymer-coated rolls arranged in calenders require cooling so that they will operate optimally. By means of such cooling, attempts are made to keep the end and lateral areas of the roll at a uniform temperature so that the effect of crown formation by the effect of heat is minimized.
For cooling, a so-called displacement tube technique has been applied.
The principle of the displacement tube technique is briefly as follows: water at the required temperature is passed to the end of the roll by means of a water coupling, water circulates in the interior of the roll along a space between an inner tube and an outer tube to the opposite end of the roll, and at the opposite end of the roll there is a water coupling through which the water is passed out of the roll. The space between the inner tube and the outer tube in the roll is usually quite small. In this manner, even though the amounts of water are quite small, attempts are made to keep the flow sufficiently large in order to meet the requirement of a uniform temperature in the end and lateral areas of the roll.
It has been laborious and difficult to fit the inner tube and the outer tube one inside the other. First, it has been necessary to measure and to manufacture the inner tube separately for each roll because the diameters of the outer tube vary from roll to roll. Then, in the installation stage, it has been necessary to cool the inner tube with nitrogen in order to fit the tube into the interior of the outer tube. Thus, manufacturing rolls with inner tubes has been typically a time-consuming and technically and economically unfavorable procedure.
It is an object of the present invention is to provide a solution for installing an inner tube in a roll by whose means the difficulties related to the prior art methods are overcome.
It is another object of the present invention to provide new and improved rolls for a paper/board machine or for a paper/board finishing device.
It is another object of the present invention to provide new and improved methods for fastening an inner tube in an interior of a roll, especially for use in a paper/board machine or paper/board finishing device.
It is yet another object of the present invention to provide an inner tube for a roll which is able to be arranged in the inside of rolls having different diameters so that the inner tube does not have to be roll-specific.
In order to attain these objects and others, in a roll in accordance with the present invention, the inner tube, by whose means the water is forced to flow along the inner face of the mantle of the roll body, is fastened to the body mantle by fastening pistons which are installed on the inner tube with a necessary spacing in the longitudinal direction whereby three pistons are arranged in the direction of the circumference. Of the pistons in the direction of the circumference, two are fixedly installed at a proper height in connection with the installation, and one is freely moving and spring-loaded. The spring-loaded piston is constructed so that, by means of hydraulics, the piston is pressed down for the time of installation of the inner tube. The pipe systems required by the hydraulics are passed along the outer face of the inner tube, preferably to the tending-side end of the roll. The pressure required by the hydraulics is produced by means of a normal hydraulic pump (the same pump by whose means the bearing is removed/fixed). After the inner tube has been installed in the correct position, the hydraulic pressure is released, and the disk springs of the spring-loaded piston press the piston against the body mantle. By means of the fixed and the spring-loaded pistons, the inner tube is kept in its position, and vibration and bending of the inner tube are prevented. The fastening at the ends is arranged either so that separate rings attached to the flange shafts by means of hexagonal socket-head bolts, on which rings the inner tube is installed with glide fitting, or, in new projects, so that alterations are made to the cast models of the flange shaft, and the end fastening face is provided directly on the flange shaft. In this manner, separate rings are not needed.
Thus, one general embodiment of a roll for a paper/board machine or finishing device comprises a roll mantle defining an interior and having an inner face, an inner tube arranged in the interior of the roll mantle and having an outer face arranged at a distance from the inner face of the roll mantle, and a plurality of fastening elements (or simply fastenings) for securing the inner tube to the roll mantle. At least one fixed fastening is positioned radially in a certain predetermined position (fixed in that it includes a piston which is not movable during the installation procedure) and a displaceable fastening is arranged to be displaceable in a radial direction of the inner tube (displaceable in that it includes a component which is movable during the installation procedure). The inner tube may comprise apertures at first and second ends and the roll further comprises first and second shafts arranged at first and second ends of the roll mantle. Each shaft includes a flow passage communicating with a space between the inner face of the roll mantle and the outer face of the inner tube via the apertures in the inner tube.
The displaceable fastening comprises a spindle part having a head part and biasing means, e.g., a spring unit of one or more springs, for urging the head part against the inner face of the roll mantle. It may also comprise an interior space receivable of pressure fluid defined adjacent the spindle part. The biasing means are thus arranged such that upon removal of pressure fluid from the interior space (which occurs after the inner tube is installed in the interior of the roll), the head part is urged against the inner face of the roll mantle. The displaceable fastening may also comprise a piston part, whereby the interior space is defined between the piston part and the spindle part, and a sleeve defining a first interior space and a second interior space having a diameter smaller than a diameter of the first interior space and having an edge portion in the vicinity of an inlet opening of the first interior space. The sleeve defines an inside shoulder between the first and second interior spaces. The spindle part may include a rod connected to the head part and surrounded by the spring(s) of the spring unit. An intermediate disk may be arranged on the shoulder and a cotter ring may be provided to lock the disk against the shoulder. The disk includes a central opening through which the rod of the spindle part passes. The piston part includes an inner bore having threading and the rod includes a threading in engagement with the threading of the piston part. Further, the fastening may include an end disk arranged at an end of the inner bore of the piston part, and a cotter coupled to the piston part for preventing rotation of the piston part. The cotter is guided in a hole in the sleeve of the fastening. In some embodiments, the sleeve includes a duct for allowing passage of pressure fluid into and from the interior space in the fastening.
There are preferably two fixed fastenings. Each fixed fastening comprises a sleeve and a screw arranged in the sleeve and having an outer face adapted to be pressed against the inner face of the roll mantle. The screw is rotatable relative to the sleeve to provide adjustable extension of the screw from the sleeve, which rotation is effected prior to installation or insertion of the inner tube into the interior of the roll mantle. The screw is then locked in its position and then the inner tube is inserted into the interior of the roll. In some embodiments, the screw has a spindle part having a threaded outer surface and a backup part wider than the spindle part. The interior of the sleeve defines a wide recess and an end bore having a threading. The spindle part of the screw threadingly engages with the threading of the end bore of the sleeve. The backup part includes a curved outer face adapted to be pressed against the inner face of the roll mantle upon rotation of the screw relative to the sleeve.
In the method for fastening an inner tube into an interior of a roll for a paper/board machine or finishing device, at least one first fastening is arranged in the inner tube at a location along an axis of the inner tube, each first fastening having an extension projectable above the outer face of the inner tube and designed to be fixed in position during installation of the inner tube into the interior of the roll. A second fastening is arranged in the inner tube at the same axial location as the first fastening(s), the second fastening having a displaceable spindle part movable between first and second position whereby the spindle part projects further above the outer face of the inner tube in the second position (although in the first position, the spindle part does not necessarily have to project above the outer face of the inner tube). The position of the extension of each first fastening is adjusted and preferably fixed at a desired radial projecting position prior to installation of the inner tube in the interior of the roll. The inner tube is then inserted into the mantle of the roll while maintaining the spindle part of the second fastening in the first position. The spindle part of the second fastening is then displaced into the second position and urged against the inner face of the mantle, e.g., by the decompression of springs in a spring unit.
The spindle part of the second fastening may be maintained in the first position by coupling a pipe to the second fastening, extending the pipe to one of the ends of the inner tube and directing a medium through the pipe to cause displacement of the spindle part of the second fastening to the first position such that control of the displacement of the spindle part of the second fastening is effected from the end of the inner tube. Similarly, the spindle part of the second fastening may be maintained in the first position and caused to be displaced into the second position by coupling a pipe to the second fastening, arranging a piston part and a stationary disk in the second fastening, arranging at least one spring between a head part of the spindle part and the disk, and controlling the flow of pressure fluid through the pipe into and from a space between the disk and the piston part. When the pressure fluid flows into the space, the spindle part is moved to the first position and the at least one spring is compressed, and when the pressure fluid flows from the space, the spindle part is moved to the second position upon decompression of the at least one spring.
In the following, the invention will be described in detail with reference to some exemplifying embodiments of the invention illustrated in the figures in the accompanying drawing. However, the invention is by no means strictly confined to the details of the illustrated embodiments alone.